1. Technical Field
The present invention relates to a switch.
2. Related Art
Conventionally, there is well known a switch that is turned on and off by sliding a slider, which is of a movable contact retained by an operating member, on a fixed contact in response to a lever operation.
The conventional switches are disclosed in Japanese Unexamined Patent Publication Nos. 2009-4175, H8-227630, 2012-138221, and 2005-19139 and Japanese Patent No. 3956806. In these switches, the switch that switches a circuit from a closed state to an opened state by performing a pressing operation includes a normally-closed fixed contact having a conductive region and an insulating region as the fixed contact. The circuit is switched from the closed state to the opened state by sliding the slider from the conductive region to the insulating region of the fixed contact.
However, unfortunately an insulation failure is generated with increased number of repetitive opening and closing movement in the conventional switch, which includes the normally-closed fixed contact and switches the circuit from the closed state to the opened state by sliding the slider that is of the movable contact on the normally-closed fixed contact.
In the conventional switch, the slider slides on the conductive region and the insulating region of the normally-closed fixed contact during the opening and closing operation. The repetitive opening and closing movement abrades the conductive region, and metallic abrasion powders are deposited on the conductive region and the insulating region. FIG. 9 is a photograph illustrating the metallic abrasion powders deposited on a sliding surface of the slider in the normally-closed fixed contact. As a result, insulation performance of the switch degrades to generate the insulation failure.
An arc discharge is generated between the normally-closed fixed contact and the slider in the case of the opening and closing operation of a high-capacity current. An insulating resin or a grease, which constitutes the insulating region, is carbonized, and therefore the insulation performance of the switch degrades to generate the insulation failure.